This invention relates to the field of distributed object computing in a client-server environment, and more particularly, this invention relates to a Common Object Request Broker Architecture (CORBA) used in distributed object computing.
The increase in the number of communication industries, internet technologies, and worldwide web (WWW) users has resulted in a large number of programs using Object Oriented Programming (OOP) techniques. This type of programming is applicable to client-server computing using a distributed computing model where client applications request services from a server. The client applications and server processes typically operate on different computers interconnected to each other via a network, such as the internet. As is well known, the client application sends messages to the server via the network, while the server or program listens for client requests that are transmitted back via the network. The servers receive requests and perform actions.
In distributed object computing and object-oriented programming, objects are pieces of software that encapsulate an internal state and make it accessible through an interface, including object operations and attributes that are remotely accessible. A naming service can be used to connect portions of the interface. Clients, in turn, invoke operations on the remote object, which acts as a server. Objects belong to classes that are incrementally modified through inheritance. Examples of well-known object-oriented languages using these types of objects include Java or C++. The objects are collections of operations that share a state, where the operations determine the messages (or calls) to which the object can respond. This shared state is hidden from the outside world and only accessible to the objects operations.
One key aspect of object oriented programming is the reuse of programming effort by the reuse of sub-classes. Physical resources can have components that can be modeled in an object oriented manner and this programming effort can be re-used. Different programs, such as Java or C++, enable direct reuse of classes, but usually only if the same language can be bound or linked together. With the rise of the internet and larger communications networks, control and data processing functions are distributed among many geographically spaced computers at different locations making control over interfacing and communication among the different physical devices problematic.
Internet applications are becoming increasingly more difficult to communicate with each other because different machines with one architecture and code must communicate with other machines that are built around different architectures and codes. In response to this problem, the Object Management Group (OMG) has developed the Common Object Request Broker Architecture (CORBA) specification, which is a protocol for interprocess communication in a heterogenous environment. This infrastructure allows objects to converse independent of specific platforms and techniques used to implement the objects. As a result, there is interoperability between objects and those built-in, different languages that operate on different machines in a heterogenous distributed environment.
The CORBA architecture uses an Interface Definition Language (IDL), which is a declarative language similar to C++. It includes interfaces that are similar to classes of interface inheritance with input and output arguments and data types that are passed along with an operation. The Interface Definition Language declares remotely accessible server objects in a platform in programming language-neutral manner without implementation. The CORBA architecture also includes an Object Request Broker (ORB), which allows a client to communicate to an object through an object reference that acts as a pointer. The Object Request Broker finds a server object for a client request and prepares the object to receive the request, transmit the request from the client to the server object, and return output arguments back to the client application. Thus, an Object Request Broker provides an object-oriented Request Procedure Call (RPC) facility.
Other elements of the CORBA architecture include a Portable Object Adaptor (POA), Dynamic Invocation Interface (DII), Internet Inter-ORB Protocol (IIOP), and an Interface and Implementation Repository, as known to those skilled in the art.
One of the drawbacks of most CORBA architectures is that once the definition of the interface application provides or uses has changed, it should be rebuilt in order to work with the new interface even if the dynamic invocation is used. Opposite to programming languages, such as C++ and Java, usually used to build CORBA clients and servers, use of scripting language does not require extra compilation steps. The changes made to interfaces obtain instant support by script(s) modification.
There are some prior art CORBA gateways that approach this problem. Some scriptable interface specifications are supported by the Object Management Group. For example, one CORBA script language implementation allows CORBA applications (or services) to be revealed to a non-CORBA client. This type of CORBA universal gateway has been used before and is not tied to a particular scripting language. The CORBA object is serialized to HTML or a Simple Object Access Protocol (SOAP) and published. There are also several implementations of Extensible Markup Language (XML) to CORBA bridges. These capabilities, however, are more restrictive and are not used for dynamic CORA systems implementation.
It is desirable, however, that a more sophisticated CORBA gateway system would allow a server and scripting language to be implemented such that a CORBA client can accept this server from the non-CORBA device or program.
The present invention is advantageous and allows a service that is not specified through a Common Object Request Broker Architecture (CORBA) to be exposed to a client that is CORBA specified. A SOAP request can be prepared by interactive scripting as part of a client""s business logic function that is operable via a SOAP interface. References can be created and maintained to virtual CORBA services via a virtual CORBA service object. The virtual CORBA services can be addressed by a set of HTTP Uniform Resource Locators (URL""s). The references can be exposed as a monolithic CORBA service. The CORBA name value list data types can be serialized SOAP messages. An Internet Inter-ORB Protocol (IIOP) callback can be generated using a Simple Object Access Protocol (SOAP) message.
In yet another aspect of the present invention, Interface Definition Language (IDL) method calls can be translated to the SOAP messages. A specified method implementation HTTP uniform resource locator can also be transmitted via a virtual CORBA service object that forms a CORBA gateway.